mirror of
https://github.com/sockspls/badfish
synced 2025-07-13 04:29:15 +00:00
Speed up kpk initialization
The trick is to classify more position at first cycle, so to reduce following work. Speed up is of about 50% ! Also some cleanup while there. Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
parent
4c9d570e43
commit
15683034a7
2 changed files with 110 additions and 123 deletions
229
src/bitbase.cpp
229
src/bitbase.cpp
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@ -28,15 +28,17 @@ namespace {
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RESULT_UNKNOWN,
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RESULT_INVALID,
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RESULT_WIN,
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RESULT_LOSS,
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RESULT_DRAW
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};
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struct KPKPosition {
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Result classify_knowns(int index);
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Result classify(int index, Result db[]);
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private:
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void from_index(int index);
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bool is_legal() const;
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bool is_immediate_draw() const;
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bool is_immediate_win() const;
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Result classify_white(const Result db[]);
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Result classify_black(const Result db[]);
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Bitboard wk_attacks() const { return StepAttacksBB[WK][whiteKingSquare]; }
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Bitboard bk_attacks() const { return StepAttacksBB[BK][blackKingSquare]; }
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Bitboard pawn_attacks() const { return StepAttacksBB[WP][pawnSquare]; }
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@ -46,13 +48,11 @@ namespace {
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};
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// The possible pawns squares are 24, the first 4 files and ranks from 2 to 7
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const int IndexMax = 2 * 24 * 64 * 64; // color * wp_sq * wk_sq * bk_sq
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const int IndexMax = 2 * 24 * 64 * 64; // color * wp_sq * wk_sq * bk_sq = 196608
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// Each uint32_t stores results of 32 positions, one per bit
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uint32_t KPKBitbase[IndexMax / 32];
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Result classify_wtm(const KPKPosition& pos, const Result bb[]);
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Result classify_btm(const KPKPosition& pos, const Result bb[]);
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int compute_index(Square wksq, Square bksq, Square wpsq, Color stm);
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}
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@ -65,64 +65,49 @@ uint32_t probe_kpk_bitbase(Square wksq, Square wpsq, Square bksq, Color stm) {
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}
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void init_kpk_bitbase() {
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void kpk_bitbase_init() {
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Result bb[IndexMax];
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Result db[IndexMax];
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KPKPosition pos;
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bool repeat;
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int index, bit, repeat = 1;
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// Initialize table
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for (int i = 0; i < IndexMax; i++)
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{
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pos.from_index(i);
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bb[i] = !pos.is_legal() ? RESULT_INVALID
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: pos.is_immediate_draw() ? RESULT_DRAW
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: pos.is_immediate_win() ? RESULT_WIN : RESULT_UNKNOWN;
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}
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for (index = 0; index < IndexMax; index++)
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db[index] = pos.classify_knowns(index);
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// Iterate until all positions are classified (30 cycles needed)
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do {
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repeat = false;
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for (int i = 0; i < IndexMax; i++)
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if (bb[i] == RESULT_UNKNOWN)
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{
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pos.from_index(i);
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bb[i] = (pos.sideToMove == WHITE) ? classify_wtm(pos, bb)
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: classify_btm(pos, bb);
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if (bb[i] != RESULT_UNKNOWN)
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repeat = true;
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}
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} while (repeat);
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while (repeat)
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for (repeat = index = 0; index < IndexMax; index++)
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if ( db[index] == RESULT_UNKNOWN
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&& pos.classify(index, db) != RESULT_UNKNOWN)
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repeat = 1;
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// Map 32 position results into one KPKBitbase[] entry
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for (int i = 0; i < IndexMax / 32; i++)
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for (int j = 0; j < 32; j++)
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if (bb[32 * i + j] == RESULT_WIN || bb[32 * i + j] == RESULT_LOSS)
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KPKBitbase[i] |= (1 << j);
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for (index = 0; index < IndexMax / 32; index++)
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for (bit = 0; bit < 32; bit++)
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if (db[32 * index + bit] == RESULT_WIN)
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KPKBitbase[index] |= (1 << bit);
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}
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namespace {
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// A KPK bitbase index is an integer in [0, IndexMax] range
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//
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// Information is mapped in this way
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//
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// bit 0: side to move (WHITE or BLACK)
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// bit 1- 6: black king square (from SQ_A1 to SQ_H8)
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// bit 7-12: white king square (from SQ_A1 to SQ_H8)
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// bit 13-14: white pawn file (from FILE_A to FILE_D)
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// bit 15-17: white pawn rank - 1 (from RANK_2 - 1 to RANK_7 - 1)
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// A KPK bitbase index is an integer in [0, IndexMax] range
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//
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// Information is mapped in this way
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//
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// bit 0: side to move (WHITE or BLACK)
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// bit 1- 6: black king square (from SQ_A1 to SQ_H8)
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// bit 7-12: white king square (from SQ_A1 to SQ_H8)
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// bit 13-14: white pawn file (from FILE_A to FILE_D)
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// bit 15-17: white pawn rank - 1 (from RANK_2 - 1 to RANK_7 - 1)
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int compute_index(Square wksq, Square bksq, Square wpsq, Color stm) {
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assert(square_file(wpsq) <= FILE_D);
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int p = int(square_file(wpsq)) + 4 * int(square_rank(wpsq) - 1);
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int r = int(stm) + 2 * int(bksq) + 128 * int(wksq) + 8192 * p;
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int p = square_file(wpsq) + 4 * (square_rank(wpsq) - 1);
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int r = stm + 2 * bksq + 128 * wksq + 8192 * p;
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assert(r >= 0 && r < IndexMax);
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@ -131,73 +116,79 @@ namespace {
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void KPKPosition::from_index(int index) {
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int s = (index / 8192) % 24;
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sideToMove = Color(index % 2);
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blackKingSquare = Square((index / 2) % 64);
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whiteKingSquare = Square((index / 128) % 64);
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pawnSquare = make_square(File(s % 4), Rank(s / 4 + 1));
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int s = index >> 13;
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sideToMove = Color(index & 1);
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blackKingSquare = Square((index >> 1) & 63);
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whiteKingSquare = Square((index >> 7) & 63);
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pawnSquare = make_square(File(s & 3), Rank((s >> 2) + 1));
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}
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bool KPKPosition::is_legal() const {
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Result KPKPosition::classify_knowns(int index) {
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from_index(index);
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// Check if two pieces are on the same square
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if ( whiteKingSquare == pawnSquare
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|| whiteKingSquare == blackKingSquare
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|| blackKingSquare == pawnSquare)
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return false;
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return RESULT_INVALID;
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if (sideToMove == WHITE)
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{
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if ( bit_is_set(wk_attacks(), blackKingSquare)
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|| bit_is_set(pawn_attacks(), blackKingSquare))
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return false;
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}
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else if (bit_is_set(bk_attacks(), whiteKingSquare))
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return false;
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return true;
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}
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bool KPKPosition::is_immediate_draw() const {
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if (sideToMove == BLACK)
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{
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Bitboard wka = wk_attacks();
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Bitboard bka = bk_attacks();
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// Case 1: Stalemate
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if ((bka & ~(wka | pawn_attacks())) == EmptyBoardBB)
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return true;
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// Case 2: King can capture pawn
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if (bit_is_set(bka, pawnSquare) && !bit_is_set(wka, pawnSquare))
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return true;
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}
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else
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{
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// Case 1: Stalemate (possible pawn files are only from A to D)
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if ( whiteKingSquare == SQ_A8
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&& pawnSquare == SQ_A7
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&& (blackKingSquare == SQ_C7 || blackKingSquare == SQ_C8))
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return true;
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}
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return false;
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}
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bool KPKPosition::is_immediate_win() const {
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// Check if a king can be captured
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if ( bit_is_set(wk_attacks(), blackKingSquare)
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|| (bit_is_set(pawn_attacks(), blackKingSquare) && sideToMove == WHITE))
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return RESULT_INVALID;
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// The position is an immediate win if it is white to move and the
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// white pawn can be promoted without getting captured.
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return sideToMove == WHITE
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&& square_rank(pawnSquare) == RANK_7
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&& whiteKingSquare != pawnSquare + DELTA_N
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&& ( square_distance(blackKingSquare, pawnSquare + DELTA_N) > 1
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|| bit_is_set(wk_attacks(), pawnSquare + DELTA_N));
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if ( square_rank(pawnSquare) == RANK_7
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&& sideToMove == WHITE
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&& whiteKingSquare != pawnSquare + DELTA_N
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&& ( square_distance(blackKingSquare, pawnSquare + DELTA_N) > 1
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|| bit_is_set(wk_attacks(), pawnSquare + DELTA_N)))
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return RESULT_WIN;
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// Check for known draw positions
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//
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// Case 1: Stalemate
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if ( sideToMove == BLACK
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&& (bk_attacks() & ~(wk_attacks() | pawn_attacks())) == EmptyBoardBB)
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return RESULT_DRAW;
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// Case 2: King can capture pawn
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if ( sideToMove == BLACK
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&& bit_is_set(bk_attacks(), pawnSquare) && !bit_is_set(wk_attacks(), pawnSquare))
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return RESULT_DRAW;
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// Case 3: Black king in front of white pawn
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if ( blackKingSquare == pawnSquare + DELTA_N
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&& square_rank(pawnSquare) < RANK_7)
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return RESULT_DRAW;
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// Case 4: White king in front of pawn and black has opposition
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if ( whiteKingSquare == pawnSquare + DELTA_N
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&& blackKingSquare == pawnSquare + DELTA_N + DELTA_N + DELTA_N
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&& square_rank(pawnSquare) < RANK_5
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&& sideToMove == WHITE)
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return RESULT_DRAW;
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// Case 5: Stalemate with rook pawn
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if ( blackKingSquare == SQ_A8
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&& square_file(pawnSquare) == FILE_A)
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return RESULT_DRAW;
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return RESULT_UNKNOWN;
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}
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Result classify_wtm(const KPKPosition& pos, const Result bb[]) {
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Result KPKPosition::classify(int index, Result db[]) {
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// If one move leads to a position classified as RESULT_LOSS, the result
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from_index(index);
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db[index] = (sideToMove == WHITE ? classify_white(db) : classify_black(db));
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return db[index];
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}
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Result KPKPosition::classify_white(const Result db[]) {
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// If one move leads to a position classified as RESULT_WIN, the result
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// of the current position is RESULT_WIN. If all moves lead to positions
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// classified as RESULT_DRAW, the current position is classified RESULT_DRAW
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// otherwise the current position is classified as RESULT_UNKNOWN.
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@ -208,13 +199,13 @@ namespace {
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Result r;
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// King moves
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b = pos.wk_attacks();
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b = wk_attacks();
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while (b)
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{
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s = pop_1st_bit(&b);
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r = bb[compute_index(s, pos.blackKingSquare, pos.pawnSquare, BLACK)];
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r = db[compute_index(s, blackKingSquare, pawnSquare, BLACK)];
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if (r == RESULT_LOSS)
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if (r == RESULT_WIN)
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return RESULT_WIN;
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if (r == RESULT_UNKNOWN)
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@ -222,26 +213,24 @@ namespace {
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}
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// Pawn moves
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if (square_rank(pos.pawnSquare) < RANK_7)
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if (square_rank(pawnSquare) < RANK_7)
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{
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s = pos.pawnSquare + DELTA_N;
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r = bb[compute_index(pos.whiteKingSquare, pos.blackKingSquare, s, BLACK)];
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s = pawnSquare + DELTA_N;
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r = db[compute_index(whiteKingSquare, blackKingSquare, s, BLACK)];
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if (r == RESULT_LOSS)
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if (r == RESULT_WIN)
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return RESULT_WIN;
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if (r == RESULT_UNKNOWN)
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unknownFound = true;
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// Double pawn push
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if ( square_rank(s) == RANK_3
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&& s != pos.whiteKingSquare
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&& s != pos.blackKingSquare)
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if (square_rank(s) == RANK_3 && r != RESULT_INVALID)
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{
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s += DELTA_N;
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r = bb[compute_index(pos.whiteKingSquare, pos.blackKingSquare, s, BLACK)];
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r = db[compute_index(whiteKingSquare, blackKingSquare, s, BLACK)];
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if (r == RESULT_LOSS)
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if (r == RESULT_WIN)
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return RESULT_WIN;
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if (r == RESULT_UNKNOWN)
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@ -251,14 +240,12 @@ namespace {
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return unknownFound ? RESULT_UNKNOWN : RESULT_DRAW;
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}
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Result classify_btm(const KPKPosition& pos, const Result bb[]) {
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Result KPKPosition::classify_black(const Result db[]) {
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// If one move leads to a position classified as RESULT_DRAW, the result
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// of the current position is RESULT_DRAW. If all moves lead to positions
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// classified as RESULT_WIN, the current position is classified as
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// RESULT_LOSS. Otherwise, the current position is classified as
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// RESULT_UNKNOWN.
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// classified as RESULT_WIN, the position is classified as RESULT_WIN.
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// Otherwise, the current position is classified as RESULT_UNKNOWN.
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bool unknownFound = false;
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Bitboard b;
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@ -266,11 +253,11 @@ namespace {
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Result r;
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// King moves
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b = pos.bk_attacks();
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b = bk_attacks();
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while (b)
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{
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s = pop_1st_bit(&b);
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r = bb[compute_index(pos.whiteKingSquare, s, pos.pawnSquare, WHITE)];
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r = db[compute_index(whiteKingSquare, s, pawnSquare, WHITE)];
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if (r == RESULT_DRAW)
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return RESULT_DRAW;
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@ -278,7 +265,7 @@ namespace {
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if (r == RESULT_UNKNOWN)
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unknownFound = true;
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}
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return unknownFound ? RESULT_UNKNOWN : RESULT_LOSS;
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return unknownFound ? RESULT_UNKNOWN : RESULT_WIN;
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}
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}
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@ -39,7 +39,7 @@ using namespace std;
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extern bool execute_uci_command(const string& cmd);
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extern void benchmark(int argc, char* argv[]);
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extern void init_kpk_bitbase();
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extern void kpk_bitbase_init();
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int main(int argc, char* argv[]) {
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@ -52,7 +52,7 @@ int main(int argc, char* argv[]) {
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// Startup initializations
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init_bitboards();
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Position::init();
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init_kpk_bitbase();
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kpk_bitbase_init();
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init_search();
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Threads.init();
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